I, for one, can't see any speed difference between a program written in Pascal (Total Commander, which I use every day) and one written in C++ (Windows Explorer).
File browsers are probably the worst example you could use here. The actual file manipulations are handled by the OS. The rest of it is just displaying lists of files, so no real speed difference would be noticed in different languages/programs. Most of the time the file browser is just sitting there waiting for user interaction.
The programs that do benefit from speed aren't file browsers.
You can’t compare apples to elephants here.